Core Java Technology Section Index | Page 118

Can I persist my objects using serialization instead of using a relational or object database?

How should I declare fields within my serializable class to prevent them from being serialized?

Sun provides a Design FAQ at http://java.sun.com/products/jdk/1.2/docs/guide/collections/designfaq.html that answers many questions concerning the design of the framework.more

The Map interface can be used to count the number of times a word/object appears. The following program demonstrates counting word frequency from the command line: import java.util.*; public cl...more

No pointers does not mean no reference variables. You just can't deference them as you can in C/C++ or perform pointer arithmetic. You can still use abstract data types that require dynamic data s...more

You need to use a new Comparator, not the default Comparable. The String class comes with a special Comparator you can use: String.CASE_INSENSITIVE_ORDER.

You cannot directly make an array larger. You must make a new (larger) array and copy the original elements into it, usually with System.arraycopy(). If you find yourself frequently doing this, th...more

This is actually outside the scope of the Collections Framework. Instead, it is part of the java.text package with the Collator and CollationKey classes. The following example demonstrates this c...more

The Collections.reverseOrder() method returns a Comparator that sorts objects that implement the Comparable interface in reverse order.

The Arrays.asList() method provides a fixed-length List view of an array, where changes to the List are stored in the original array. The Arrays class also provides additional support methods for ...more

Enumeration enum = ...; while (enum.hasMoreElements()) { Object element = iterator.nextElement(); // process element }

You need to wrap the primitive data type into one of the wrapper classes found in the java.lang package, like Integer, Float, or Double, as in: Integer in = new Integer(5); more

A red-black tree is a binary search tree where every node has two children or is a leaf. It ensures O(log N) search times, at a cost of a more complicated insertion (and deletion) process. In a re...more

The comp.lang.java.programmer newsgroup is probably your best bet for Collections Framework questions. There is mailing list specific to ObjectSpace JGL-questions that you can subscribe to at http...more

Because a synchronized HashMap requires an extra method call, a Hashtable is faster for synchronized access.